1. Technical Field
The present invention relates to a head gimbal assembly for a magnetic disk file and more specifically to a head gimbal assembly formed from a laminated material in which the electrical lines are formed in one layer of the laminate.
2. Background Information
Magnetic recording disk files that utilize a transducer mounted on a slider for reading and/or writing data on at least one rotatable disk are well-known in the art. In such systems, the slider is typically attached to an actuator arm by a suspension system.
Many suspension systems (also called head gimbal assemblies) include a flexure that is positioned in some manner between the slider and the suspension. For example, R. Watrous, in U.S. Pat. No. 4,167,765, discloses a flexure that is added onto a stiffened member. Blaeser et. al, in U.S. Pat. No. 5,198,945, disclose another design that utilizes the material of the suspension as the flexure.
Systems are known in which the slider is positioned in an open space formed between two flexure arms. For example, FIG. 6 illustrates a head gimbal assembly described by Johnson et al. in U.S. Pat. No. 5,331,489, in which the slider is positioned between two flexure arms and the electrical attachment to the slider is made by four discrete wires. The discrete wires are terminated to the back of the slider and four wires are utilized to accommodate magnetoresistive (MR) head technology.
The use of solder balls for attaching the slider to a slider support means is known in the art. For example, Ainslie et al., in U.S. Pat. No. 4,761,699, disclose the use of reflowed solder balls for making both the mechanical attachment of the slider to the suspension and the electrical connection of the transducer to the disk file read/write electronics. Additionally, Ainslie et al., in U.S. Pat. No. 4,789,914, disclose a soldering technique for making an electrical attachment of a cable to a transducer on the backside of a slider.
The use of laminated materials for constructing slider suspension systems is also known in the art. For example, Erpelding et al., in U.S. Pat. No. 4,996,623, disclose a suspension system comprised of a sheet of polyimide material sandwiched between two metal layers. U.S. Pat. No. 4,996,623 also discloses that a plurality of conductors can be formed in the copper layer of the suspension for providing electrical connections to the slider.
Additionally, the use of discrete layers for constructing the suspension is also known. For example, G. Oberg, in U.S. Pat. No. 4,819,094, discloses a suspension system in which flexible copper conductors are sandwiched between a pair of polyimide films.
Briefly, the preferred embodiment of the present invention is a head gimbal assembly comprising a slider support member for holding a slider, a load beam for applying a load to the slider and an electrical cable extending along the backside of the load beam.
The head gimbal assembly is a single piece constructed from a laminated material comprised of a conductor layer, a dielectric layer and a support layer. The conductor layer is comprised of a high strength electrically conductive material such as a high strength copper alloy. The dielectric layer is comprised of an electrically insulating material such as a polyimide, Teflon or epoxy. The support layer is comprised of a more rigid material such as stainless steel, titanium or beryllium copper.
The electrical cable is positioned for connection to the backside of a slider and is comprised of the conductor and dielectric layers of the laminated material. The conductor layer is positioned on the dielectric layer and a plurality of elongated strips are formed in the conductor layer, with a space separating each of the elongated strips. The dielectric layer is positioned between the backside surface of the slider and the conductor layer, and between the backside surface of the load beam and the conductor layer, to prevent electrical shorting.
In other embodiments, the electrical lines extend along the backside or frontside of the load beam and are terminated to the trailing edge of the slider.